INCLUSION OF SPIN-LABELED MOLECULES IN THE SOLID PHASE OF CYCLODEXTRINS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 用TEMPOL/TEMPAMINE制备了β-和γ-环糊精（CD）与自旋标记化合物：几种正十二烷氧基硬脂酸和C8和C16脂肪酸的酯/酰胺的包合物，并在170 GHz和X波段用高频ESR研究了它们。CD结晶水合物的光谱显示出快速的近理想轴向旋转模式，对于doxylstearic acids，该模式是关于Z轴的，而对于克里思衍生物，该模式是关于X轴的。脱水的结晶停止Z-旋转的doxystearic酸，但对X-旋转的化合物的动力学的影响较小。该谱可作为ESR各向异性运动的影响和高频ESR优异的取向分辨率的很好的说明性例子，用于讲座和研讨会。在HF，一旦运动在频谱中是可辨别的，就可以辨别运动围绕哪个轴发生。 固体CD相中分子的一个显著特征是在非常低的温度下可检测到的迁移率。HF ESR表明g-张量值的平均值，因此，分子运动开始于20 K。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We prepared inclusion complexes of beta and gamma cyclodextrins (CD) with spin labeled compounds: several n-doxylstearic acids and esters/amides of C8 and C16 fatty acids with TEMPOL/TEMPAMINE and studied them by HF ESR at 170 GHz and X-Band. The spectra in CD crystallohydrate show patterns of fast near-ideal axial rotation, which is about Z-axis for doxylstearic acids and about X-axis for TEMPO derivatives. Dehydration of the crystallohydrate stops Z-rotation of doxystearic acids but has less effect on the dynamics of the X-rotating compounds. The spectra can be used at lectures and workshops as good illustrative examples for the effects of anisotropic motion in ESR and excellent orientation resolution of HF ESR. At HF, once motion is discernable in the spectrum, one can discern about which axis the motion occurs. A striking feature of molecular in the solid CD phase is detectable mobility at very low temperatures. HF ESR indicates averaging of the g-tensor values and, hence, molecular motion starting at 20K.